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July 16, R929. R BERTHQN 31,721,244

FILM FOR LENTICULAR SCREEN COLOR PHOTOGRAPHY AND PROCESS OF MAKING THESAME Filed June 17, 1927 a Microscopc m BY M A770 A [r Fatentec'l July11$, F929.

entree srares Iii/21,244

PATENT @FFEQE RODOLPHE BERTHON, OF NEUILLY, FRANCE, ASSIGNOR TO THESOCIETE CIVILE POUR LE'IUDE DE LA PHOTOGRAPHIE ET DE LA CINEMATOGRAPHIEAU COULE'URS, OF

NE'UILLY, FRANCE.

FILM FOR LENTICULAR-SCREEN COLOR PHOTOGRAPHY AND PROCESS OF MAKING THESAME.

Application filed June 17, 1927, Serial No. 199.559, and in France July20, 1926.

The object of my invention is to provide a process for obtainingreticulated films suitable for projection in colour on a screen butrequiring no treatment with liquid reagents;

the invention also residing in the film itself.

The accompanying drawing shows an enlarged sectional View of such afilm. which may, for example, be constituted as follows:

A sheet A constituting the support and 19 which may be made of gelatine,celluloid, cellulose, colophony, etc. i

.A backing layer B of celluloid or of some other plastic material B laidon the surface of support A and carrying in relief microscopic 155refracting element-s D for colour selection purposes. Said layer B mayhave the microscopic refracting elements formed on it by rolling afterit has been applied to the support; it may also be directly applied tothe 20 support by means of a cylinder or of a plate suitably engraved,according to the known methods for application on fabrics.

A layer G of a substance pervious to gases (cellulose, etc.) is spreadin adhesive form on the free face of support A. Said layeris'impregnated with a substance sensitive to light but capable offorming, when unaffected by light, Very dark coloured parts under theinfluence of certain gaseous reagents, such as 0 certain azoderivatives, or mixtures of azo derivatives and phenols, developable incolours by means of simple or compound ammonias used in gaseous state.As a matter of course said layer may be formed by impregnating thesurface of support A opposite to layer B. When the sensitized layer isexposed to light through a positive photographic image,

the diazo substance is destroyed at the points reached bythe light; andafter this lightprinting the film, is subjected to the action either ofammonia vapors or of an alkali bath,

whereupon the coupling ofthe diazo substance and the- .phenol takesplace with production of a colourant, so that a positive print is thusobtained from the original positive.

The print so obtained will, therefore, be suitable for projection incolours on a screen equally as the original positive.

I claim as my invention: 1

1. A method of making reticulated film for colour projection, comprisingthe steps of applying to one face of a support of transparent plasticmaterial a backing layer'having on its outer surface a multitude ofmicroscopic refracting elements for colour-selection purposes; andapplying to the other face of said support a layer of material inadhesive form which is pervious to gas and is impregnated with alight-sensitive mixture of a diazo substance and a phenol, such mixturereacting to form very dark coloured substances in an alkalineatmosphere.

2. A method of making reticulated film for colour projection, comprisingthe steps of applying to one face of a transparent celluloid support atransparent backing layer having on its outer face a multitude ofmicroscopic refracting elements for colour-selection purposes; andapplying to the'other face of said support a layer of celluloseimpregnated with a light-sensitive mixture of a diazo substance and aphenol. such mixture reacting to form very dark coloured substances inan alkaline atmosphere.

3. A reticulated film for colour projection,

comprising a transparent support; a backing layer on one face thereofhaving on its outer surface a multitude of microscopic refractingelements for colour-selection purposes; and a layer of material on theother face of the support which is pervious to gas and is impregmatedwith a light-sensitive mixture of a diazo substance and a phenol, suchmixture reacting to form very dark coloured substances in an alkalineatmosphere.

In testimony whereof I afix my signature.

RODOLPHE BERTHON.

